The present invention relates to an organic light emitting display device (OLED) and to a method for fabricating the same, and particularly, to an organic light emitting display device provided with a partition wall structure which is capable of preventing a fade-out phenomenon when devices are driven and enhancing the image quality and to a method for fabricating the same.
Generally, an organic light emitting layer is formed between two poles in an OLED, so that when charges are injected into a positive pole, electrons and holes are coupled to form excitons for generating light having a specific wave length therefrom.
A typical OLED will be described with reference to FIG. 1 which is a cross-sectional view schematically showing a structure of a typical OLED.
Referring to FIG. 1, the OLED includes an anode electrode 13 which is a transparent electrode on a glass substrate 11 and is used as a positive pole, a hole injecting layer 15, a light emitting layer 17 and an electron injecting layer 19 that are sequentially stacked, and a cathode electrode 21 used as a negative pole on the electron injecting layer 19.
With such a typical OLED, when a driving voltage is supplied to the anode electrode 13 and the cathode electrode 21, holes in the hole injecting layer 15 and electrons in the electron injecting layer 19 respectively move towards the light emitting layer 17, thereby exciting a fluorescent material in the light emitting layer 17.
The typical OLED has advantages such as being capable of driving at a low voltage, a high light emitting efficiency, a broad viewing angle, a rapid response speed and the like.
The organic materials used in the OLED are divided into a monomeric (so-called “mono-molecule”) type and a high molecular weight (so-called “high molecule”) type according to the kind of the organic material used.
The OLEDs can be divided into a monomolecular type OLED using a mono-molecule organic material, a high molecular type OLED using a high molecule organic material, and a mixed type OLED using both the high molecule material and the mono-molecule material according to the particular organic materials used.
In this aspect, an OLED in accordance with the related art will be described with reference to FIG. 2.
FIG. 2 is a cross-sectional view of an OLED in accordance with the related art.
Referring to FIG. 2, the OLED in accordance with the related art includes a first electrode 53 as an anode electrode on a glass substrate 51 and a partition wall 55a having an inversely-tapered shape on the first electrode 53.
Further, an organic light emitting layer 65 and a second electrode 67 as a cathode electrode are stacked on both sides of the first electrode 53 below the inversely-tapered partition wall 55a. 
A method for fabricating the typical OLED having such a structure will be described with reference to FIGS. 3A-3D.
FIGS. 3A-3D are cross-sectional views showing a fabrication process of an OLED in accordance with the related art.
Referring to 3A, a transparent electrode layer 53 formed of a transparent electrode material such as ITO is formed on the glass substrate 51 by sputtering. The transparent electrode layer 53 serves as a first electrode for a cathode electrode.
After an organic insulating film 55 such as a silicon nitride film (SiNx) is stacked on the transparent electrode layer 53, a positive photoresist 57 is coated on the organic insulating film 55, and then a pre-bake process is performed.
Ultraviolet light 61 is irradiated to the positive photoresist 57 for exposing the positive photoresist 57 to light through a photolithography process using an exposure mask 59 for forming a partition wall, and then the exposed positive photoresist 57 is developed to form a photoresist pattern 57a as shown in FIG. 3B.
Referring to FIG. 3B, an etching process is performed using an etchant with the photoresist pattern 57a serving as a mask to selectively remove the organic insulating film 55, and thereby, the partition wall 55a is formed on the transparent electrode layer 53 as shown in FIG. 3C.
Finally, after removing the photoresist pattern 57a remaining on the partition wall 55a, an organic light emitting layer 65 and a second electrode 67 made of a conductive material such as Al so as to serve as the cathode electrode are formed on the transparent electrode layer 53 and the partition wall 55a. 
Here, though not shown in the drawings, a hole injecting layer and an electron injecting layer are stacked underneath and on the organic light emitting layer 65, respectively.
However, the OLED and the method for fabricating the same in accordance with the related art have a drawback.
Though it is not shown in the drawings, in the fabrication process of the typical OLED, an organic material is deposited by a thermal deposition method using a shadow mask, because a photolithography process is not usable for forming the organic material pattern.
However, when the shadow mask is used for the deposition, a shadow phenomenon may occur when forming an organic layer mount.
Thus, when the device is driven, an organic layer shadow phenomenon occurs at an edge portion of pixel, so that the brightness of the device may be degraded, and moreover, a fade-out, a phenomenon wherein image becomes blurred at the time of image driving, as shown at “A” in FIG. 2, may occur.